Cyclic plasticity and substructure of metals

Fatigue of metals is a consequence of cyclic plastic deformation. Fatigue properties, as well as the mechanical properties in general, are strongly dependent on the starting substructure. Moreover, the substructure undergoes changes during cyclic loading. This is valid both for the quasi-homogeneous cyclic plastic deformation in the whole cyclically loaded metal and for the highly localised cyclic plastic deformation at the crack initiation sites and later at the crack tip. The paper is devoted to the delimitation of the cyclic plasticity and its specific features, which distinguish it from the monotonic plasticity. Further, the relation of the cyclic plasticity to the substructure and damage accumulation is discussed.